Regulating system



W. H. SMITH REGULATING SYSTEM Filed May 20, 1942 March 16, 1943.

I AT NE WITNESSES:

Patented Mar. 16, 1943 REGULATING SYSTEM ,Walter H. Smith, Wilkinsburg, Pa assiznor to Westinghouse Electric 4* Manufacturing Company, East Pittsburgh, Pa, a corporation of Pennsylvania Application May 20, 1942, Serial No. 443,687

5 Claims.

This invention relates to electrical apparatus, and particularly to regulating systems.

In the electrical industry where power is supplied to loads having little counter-electromotive force, as where batteries are to be charged, attempts have been made to provide sensitive regulating apparatus for preventing overloading of the power source. Heretoiore complicated apparatus having large moving parts and adding greatly to the cost has been employed or a plurallty of electrical elements including a combi-- nation of vibrating voltage and current regu lators have been utilized. In the latter case, the inclusion of the current regulator has also added to the cost of the apparatus and has not always given the sensitive control required. This is because the current element of the regulator interferes with the operation of the voltage regulator as the movement of the vibrating element introduces voltage and current oscillatiohs.

It is an obiect of this invention to provide a regulating system responsive to the cooperative effect of changes in current and voltage for controlling the energization of a generator.

Other objects of this invention will become apparent from the following description when taken in conjunction with the accompanying drawing, in which:

Figure l is a view in elevation and partly in section of the regulating apparatus utilized in this invention, and

Fig. 2 is a diagrammatic illustration of the regulating system of this invention.

Referring to Fig. 1 of the drawing, this invention is illustrated by utilizing a vibrating type of voltage regulator it and a current control device it mounted on a panel it. The vibrating type of voltage regulator to is a modified form of the general type known to the art and generally disclosed in Patent No. 1,820,712, issued August 25, 1931, to W. Schaelchlin and assigned to the assignee of this invention.

The magnetic portion of this voltage regulator Ill comprises a magnetic core formed of the portlon or leg I6 and the portion l8 having an annular end portion 20 for completing the magnetic circuit. Coil 22 is provided for magnetizing the core or magnetic structure and is disposed about the leg l6 thereof. A smaller coil 24 connected in series circuit relation with the coil 22 is mounted upon a supporting sleeve 26 of non-magnetic metal or molded material which is disposed about the free end of the leg I6 being completely surrounded by the annular end portion 20%01 the magnetic circuit. Two identical arms 28 and 29 attached at their lower end to the opposite sides or'the metal sleeve 26 by any suitable means and disposed to pivot about the bar 30 in response to predetermined magnetic conditions are biased in a clockwise direction by the spring 32.

The annular portion of the magnetic structure it is provided with upwardly extending and spaced bracket portions 34, only one of which is shown in the drawing, i'or supporting the arms 28 and 29 and the spring 32. As illustrated each of the vanes of the brackets tit is suitably drilled for receiving a pin 38 having a grooved portion therein for providing a bearing seat for the bar 3|) which extends between the arms to and 255. Another pin lli, preferably rounded, extends between the arms 28 and it and a ring member 42 is disposed thereabout for transmitting the force of the spring 3? to the pivotally mounted arms. The spring 32 is a compression spring disposed between the bimetal strips fl l which extend between the brackets ti t and the spring end or retamer at which is held in position about the bolt is by the adjustable nut tit. the other end of the bolt being secured to the ring member 32. Prof-- erabiy the pin it is provided with 'a slot into which the ring member &2 fits for positioning the pull. of the spring on the arm assembly.

The arms 28 and 29 are disposed to vibrate about their pivot bar 35 in response to unbalanced conditions between the magnetic pull of the coils 22 and 2t and the mechanical pull of the spring 32. In order to utilize this condition for effecting switching operations, contact members 52, usually two in number, are suitably carried on a bracket St at the upper end of the arms 28 and 29 for movement to engage opposed pairs of stationary contact members 56 and 58 which are mounted on the panel 54. The two movable contact members 52 are mounted on a strap which is preferably mounted on the bracket 5 by the pin 6ll, the pin permitting slight pivotal movement or the strap and contact members carried thereby to insure proper engagement with the cooperating stationary contact members when actuated.

The current control device it utilized in this invention comprises a pile resistor 62 formed of seated against the fixed stop 12 and the flange I8 carried on the other end of the tube I4 cooperate to limit the expansion of the stack of discs 8 In order to apply pressure to the stack an elongated rod 88 is disposed to extend through the tube 14 and carries a pressure applying fiange member 82 on its one end disposed to engage the pressure plate 10. The flange member 82 is maintained in position on the rod 80 by the adjustable nut 88.

Operatively associated with the pile resistor 82 is an actuating mechanism comprising the bimetallic members 88 and 88 having the same general characteristics but mounted to oppose each other. As illustrated, each of the bimetal elements 88 and 88 is secured in spaced relation at one end thereof on a bolt member 80, the element 88 being insulated from the bolt 80 by the collar 82 and the washer 84 of insulating material. A heater element 88 is operatively associated with the bimetal element 88 and is connected to terminals 88 and I mounted in any suitable manner on the panel l4. In order to prevent the heating of the bimetal element 88 when the heater element 88 is heated, an insulating barrier I02 is disposed therebetween.

Each of the bimetal elements 88 and 88, the heater element 86 and the barrier I02 have aligned enlarged openings therein adjacent the free end of the bimetal elements through which the rod 80 of the pile resistor extends, nuts I04 and I06 being provided thereon disposed to seat against the opposed bimetal elements 88 and 88, respectively. By means of this arrangement, the bimetal elements compensate one another for changes in the ambient temperature while the bimetal element 88 functions when heated to actuate the rod 80 to compress the stack of discs 84. As the bimetal element 88 is cooled, the bimetal element 88 functions to insure the release of the pressure on the stack of discs 84.

Referring to Fig. 2, there is illustrated a regulator system in which a generator I08 is provided with an armature 0 that is connected to conductors H2 and H4 for supplying any given load (not shown). The generator I08 may be driven by any suitable prime mover (not shown), such as 9. Diesel engine, or the like, and any suitable type 01 load may be connected to the conductors H2 and H4. The generator I08 is provided with a shunt field winding H6 that is connected in series with a resistor H8 across the terminal conductors H2 and H4 of the generator.

The movable contact members 82 of the regulator or switching apparatus are carried by the arm 28 which is electrically connected to a point I20 between the field winding I I8 and the resistor H8. The stationary contact members 88 and 88 are connected through resistors I22 and M4, respectively, to conductors H2 and H4, respectively, condensers I28 and I28 being connected between the contact members 86 and the arm 28 and the contact members 58 and the arm 28, respectively, to limit or minimize arcing upon the disengagement of the contact members. As illustrated, each of the resistors I22 and I24 is provided with a mid-terminal or tap for connecting them to the conductors H2 and H4, respectively, the resistors thereby cooperating with their contact members to effect a reduction of current flowing through the contact members when they are engaged to prolong the life of the contact members. The two halves of the resistor member I24 are thus disposed to be connected in parallel circuit relation with one another and with the resistor II8 when the movable contact members 82 engage the stationary contact members 88, whereas the two halves of the resistor I22 are disposed to be connected in parallel circuit relation to one another but in shunt to the field winding I I8 when the movable contact members 82 engage the fixed contact members 88.

As illustrated, the heater element 88 of the current control device I2 is connected in circuit with the conductor H4 whereby the heat generated by the element 88 for heating the bimetal member 88 is dependent upon the load current. The regulator coils 22 and 24 are connected in series circuit relation with their series connected resistors I80, I82 and I34 across the conductors H2 and H4, a section of the resistor I being connected in parallel with the pile resistor 82. An anti-hunt resistor I38 is also connected to the conductor II4 through the resistor H8 and to the point I88 between the moving coil 24 and the stationary coil 22 or the voltage responsive device.

In operation, assuming that the generator is driven by a suitable prime mover (not shown) to supply a load such as a battery (not shown) the resistor I84 is manually adjusted to provide for so energizing the voltage responsive coils 22 and 24 that the magnetic pull of the coils balance the mechanical pull of the spring 82 for a given regulated voltage. The heater element 88 is at the same time subjected to the load current and the bimetal element 88 operates in opposition to the bimetal element 88 to tend to apply pressure on pile resistor 82. However, the nut 84 of the pile resistor is so adjusted that for all loads ranging from no load to full load, the stack of disks is unaflected by movement of the bimetal element 88 with the result that the resultant resistance of the parallel connected resistors I80 and 82 and the resistors I82 and I84 remains constant for all loads up to full load to effect the required energizatlon of the coils of the voltage responsive device. Thus for any given regulated voltage, the magnetic pull of the coils 22 and 24 can be adjusted to so balance the mechanical pull of the spring 82 that the movable contact members 82 are vibrated constantly into and out of engagement with the fixed contact members 88 for the particular regulated voltage.

If the load is decreased within the range of no load to full load, the generator voltage tends to increase and the excitation of the coils 22 and 24 tends to increase with the result that the balance between the magnetic pull or the coils 22 and 24 and the mechanical pull of the spring tends to be upset to eil'ect a faster vibration of contact members 82 into and out of engagement with. the contact members 58 to change the energization of the field H6. It the increase in the generator voltage is large enough, then the coils 22 and 24 tend to become so energized as to actuate the movable contact members 82 into vibrating contact with the contact members 88 to connect the parallel connected sections of resistor I22 in parallel with the field winding II8 to thus efiective- 1y reduce the excitation of the generator and maintain its regulated voltage.

On the other hand, if the load is increased within the range of no load to full load, the generator voltage tends to decrease and the excitation of coils 22 and 24 tends to decrease, with the result that the mechanical pull of the spring 32 tends to overcome the magnetic pull of coils 22 and 224 so that the frequency of the vibrations oi the movable contact members 52 into and out oi engagement with the fixed contact members 58 is decreased to increase the periods of time in which the contact is made to decrease the excitation of the generator and maintain its regulated voltage.

It the load is increased beyond the full load capacity oi the generatorllll then the generator voltage tends to decrease with the result that the energization of coils 22 and 24 also tends to decrease. However, as the load current increases beyond full load, the bimetal element 88 is so heated by the load current flowing through the heater element 96 that the rod 80 is actuated to apply :pressure to the pile resistor 82 to so decrease the efiective resistance of the parallel connected resistors I30 and 62 as to maintain the energization of coils 22 and 24 substantially constant whereby the balance between the magnetic pull oi. coils 22 and 24 and the mechanical pull oi spring 32 is maintained.

Thus the voltage responsive device I is operated to effect the vibrating engagement of the movable contact members 52 into and out of engagement with contact members 58 or 56 for any given overload to maintain a given regulated voltage for the generator for that particular overload condition depending upon whether the tendency of the change in the overload regulated voltage is a decrease or an increase. The regulating system thus operates to maintain a regulated voltage on the generator for all loads from no load to full load and when full load is exceeded maintains a lower regulated generator voltage for the particular overload supplied to thereby relieve the overload condition. Thus the combined effect 01 changes in the voltage and current of the generator I08 directly controls the operation of the vibrating element of the voltage responsive device for overload conditions to control the energization of the generator. With this system it is impossible to obtain interference in the voltage and current regulation because of oscillations established by the vibrating contact member, for the magnetic pull in opposition to the mechanical pull of the spring 32 is a direct measure of both the voltage and current changes, and the arm 28, therefore, has only two forces working in opposition applied thereto to determine the direction of its operation. The apparatus employed is sensitive and has a minimum of elements.

Although this invention has been described with reference to a particular embodiment thereof, it is, of course, not to be limited thereto except insofar as is necessitated by the scope of the appended claims.

I claim as my invention:

1. In a regulating system, a generator having an armature winding and a field winding the voltage of which is to be regulated, means disposed to be connected in circuit relation with the field winding to control the energization of the generator, means disposed to connect the control means in circuit with the field winding, a voltage responsive device connected across the armature winding disposed to operate the connecting means, a resistor connected in circuit relation with the voltage responsive means, and a current device responsive to a predetermined generator current disposed to vary the effective resistance of the resistor to maintain the energization of the voltage responsive device substantially constant when the generator current exceeds the predetermined value, the current device thereby cooperating with the voltage responsive device to control the operation oi the connecting means to control the energization of the generator.

2. In a regulating system, a generator having an armature winding and a field winding the voltage oi which is to be regulated, means disposed to be connected in circuit relation with the field winding to control the energization of the generator, means disposed to connect the control means in circuit with the field winding,'a voltage responsive device connected across the armature winding disposed to operate the connecting means, a pile resister connected in circuit relation with the voltage responsive means, and a thermal device responsive to a predetermined generator current disposed to operate the pile resistor to maintain the energization of the voltage responsive device substantially constant when the generator current exceeds the predetermined value, the thermal device thereby cooperating with the voltage responsive device to control the operation of the connecting means to control the energization of the generator.

3. In a regulating system, a generator having an armature winding and a field winding the voltage of which is to be regulated, means disposed to be connected in circuit relation with the field winding to control the energization of the generator, means disposed to connect the control means in circuit with the field winding, a voltage responsive device connected across the armature winding disposed to operate the connecting means, a plurality of resistors connected in parallel circuit relation with one another and in circuit relation with the voltage responsive means, one of the resistors being adjustable, and a current device responsive to a predetermined generator current disposed to adjust the adjustable resistor to vary the effective resistance of the parallel connected resistors to maintain the energization of the voltage responsive device substantially constant when the generator current exceeds the predetermined value, the current device thereby cooperating with the voltage responsive device to control the operation of the connecting means to control the energization of the generator.

4. In a regulating system, a generator having an armature winding and a field winding the voltage of which is to be regulated, means disposed to be connected in circuit relation with the field winding to control the energization of the generator, means disposed to connect the control means in circuit with the field winding, a voltage responsive device connected across the armature winding disposed to operate the connecting means, a plurality of resistors connected in parallel circuit relation with one another and in circuit relation with the voltage responsive means, one of the resistors being a pile resistor, and a thermal device responsive to a predetermined generator current disposed to operate the pile resistor to vary the efiective resistance of the parallel connected resistors to maintain the energization of the voltage responsive device substantially constant when the generator current exceeds the predetermined value, the thermal device thereby cooperating with the voltage responsive device to control the operation of the connecting means to control the energization of the generator.

5. In a regulating system, a generator having an armature winding and a field winding the voltage of which is to be regulated, means disposed to be connected in circuit relation with the ileld winding to control the energization of the generator, means disposed to connect the control means in circuit with the field winding, a voltage responsive device connected across the armature winding disposed to operate the connecting means, a pile resistor connected in circuit rela tion with the voltage responsive means, a thermal device responsive to a predetermined generator current disposed to operate the pile resistor to maintain the enersization of the voltage responsive device substantially constant when the generator current exceeds the predetermined value, the thermal device thereby cooperating with the voltage responsive device to control the operation of the connecting means to control the energization of the generator, and means associated with the thermal device to prevent changes in ambient temperature from effecting the operation 0! the thermal device.

WALTER H. BNH'I'H. 

